code: def test_network_can_preprocess_and_combine(self):
      batch_size = 3
      frames = 5
      num_actions = 2
      lstm_size = 6
      states = (
          tf.random.uniform([batch_size, frames, 1]),
          tf.random.uniform([batch_size, frames]),
      )
      preprocessing_layers = (
          tf.keras.layers.Dense(4),
          tf.keras.Sequential(
              [
                  expand_dims_layer.ExpandDims(
                      -1
                  ),  # Convert to vec size (1,).
                  tf.keras.layers.Dense(4),
              ]
          ),
      )
      network = q_rnn_network.QRnnNetwork(
          input_tensor_spec=(
              tensor_spec.TensorSpec([1], tf.float32),
              tensor_spec.TensorSpec([], tf.float32),
          ),
          preprocessing_layers=preprocessing_layers,
          preprocessing_combiner=tf.keras.layers.Add(),
          lstm_size=(lstm_size,),
          action_spec=tensor_spec.BoundedTensorSpec(
              [1], tf.int32, 0, num_actions - 1
          ),
      )
      empty_step_type = tf.constant(
          [[time_step.StepType.FIRST] * frames] * batch_size
      )
      q_values, _ = network(
          states,
          empty_step_type,
          network_state=network.get_initial_state(batch_size),
      )
      self.assertAllEqual(
          q_values.shape.as_list(), [batch_size, frames, num_actions]
      )
      # At least 2 variables each for the preprocessing layers.
      self.assertGreater(len(network.trainable_variables), 4)
  
file_path: agents/tf_agents/networks/q_rnn_network_test.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import tensorflow
  from tf_agents.environments import suite_gym
  from tf_agents.environments import tf_py_environment
  from tf_agents.networks import expand_dims_layer
  from tf_agents.networks import q_rnn_network
  from tf_agents.specs import tensor_spec
  from tf_agents.trajectories import time_step
label_desc: Use image node_id 2 for calling the QRnnNetworkTest obj's underlying member method code with example usage: obj.test_network_can_preprocess_and_combine() without return types